Backscatter factors and mass energy-absorption coefficient ratios for diagnostic radiology dosimetry

Backscatter factors, B, and mass energy-absorption coefficient ratios, (μ(en)/ρ)(w, air), for the determination of the surface dose in diagnostic radiology were calculated using Monte Carlo simulations. The main purpose was to extend the range of available data to qualities used in modern x-ray techniques, particularly for interventional radiology. A comprehensive database for mono-energetic photons between 4 and 150 keV and different field sizes was created for a 15 cm thick water phantom. Backscattered spectra were calculated with the PENELOPE Monte Carlo system, scoring track-length fluence differential in energy with negligible statistical uncertainty; using the Monte Carlo computed spectra, B factors and (μ(en)/ρ)(w, air) were then calculated numerically for each energy. Weighted averaging procedures were subsequently used to convolve incident clinical spectra with mono-energetic data. The method was benchmarked against full Monte Carlo calculations of incident clinical spectra obtaining differences within 0.3-0.6%. The technique used enables the calculation of B and (μ(en)/ρ)(w, air) for any incident spectrum without further time-consuming Monte Carlo simulations. The adequacy of the extended dosimetry data to a broader range of clinical qualities than those currently available, while keeping consistency with existing data, was confirmed through detailed comparisons. Mono-energetic and spectra-averaged values were compared with published data, including those in ICRU Report 74 and IAEA TRS-457, finding average differences of 0.6%. Results are provided in comprehensive tables appropriated for clinical use. Additional qualities can easily be calculated using a designed GUI interface in conjunction with software to generate incident photon spectra.     

Huge Isolated Port-Site Recurrence after Laparoscopic Partial Nephrectomy: A Case Report

A 66-yr-old man with pain and swelling in the right flank was referred to our clinic for diagnosis. In 2005, the patient underwent a laparoscopic partial nephrectomy for renal cancer of the lower pole of the right kidney. A computed tomography scan revealed a 20-cm tumor in the right abdominal wall, resulting in a suspected diagnosis of port-site metastasis from the first laparoscopic operation. The patient underwent open surgery, which confirmed the diagnosis. After the operation, the patient recovered rapidly.     

Aktueller Stellenwert der Laparoskopie für die Nierentransplantation

Laparoscopic techniques have not only become increasingly more important for patients on dialysis or after kidney transplantation, they also represent the operative standard procedures as almost all patients additionally suffer from concomitant diseases and do carry a higher operative risk. Therefore, these patients will derive special benefits from minimally invasive procedures offering lower morbidity and quick recovery. In centers with expertise in minimally invasive procedures, laparoscopic donor nephrectomy has already replaced open live donor nephrectomy as the standard procedure.     

Knowledge, attitudes and practices survey on organ donation among a selected adult population of Pakistan

Background  

To determine the knowledge, attitudes and practices regarding organ donation in a selected adult population in Pakistan.     

Knowledge, attitudes and practices survey on organ donation among a selected adult population of Pakistan

Background

HIV prevention research in resource-limited countries is associated with a variety of ethical dilemmas. Key amongst these is the question of what constitutes an appropriate standard of health care (SoC) for participants in HIV prevention trials. This paper describes a community-focused approach to develop a locally-appropriate SoC in the context of a phase III vaginal microbicide trial in Mwanza City, northwest Tanzania.

Methods

A mobile community-based sexual and reproductive health service for women working as informal food vendors or in traditional and modern bars, restaurants, hotels and guesthouses has been established in 10 city wards. Wards were divided into geographical clusters and community representatives elected at cluster and ward level. A city-level Community Advisory Committee (CAC) with representatives from each ward has been established. Workshops and community meetings at ward and city-level have explored project-related concerns using tools adapted from participatory learning and action techniques e.g. chapati diagrams, pair-wise ranking. Secondary stakeholders representing local public-sector and non-governmental health and social care providers have formed a trial Stakeholders' Advisory Group (SAG), which includes two CAC representatives.

Results

Key recommendations from participatory community workshops, CAC and SAG meetings conducted in the first year of the trial relate to the quality and range of clinic services provided at study clinics as well as broader standard of care issues. Recommendations have included streamlining clinic services to reduce waiting times, expanding services to include the children and spouses of participants and providing care for common local conditions such as malaria. Participants, community representatives and stakeholders felt there was an ethical obligation to ensure effective access to antiretroviral drugs and to provide supportive community-based care for women identified as HIV positive during the trial. This obligation includes ensuring sustainable, post-trial access to these services. Post-trial access to an effective vaginal microbicide was also felt to be a moral imperative.

Conclusion

Participatory methodologies enabled effective partnerships between researchers, participant representatives and community stakeholders to be developed and facilitated local dialogue and consensus on what constitutes a locally-appropriate standard of care in the context of a vaginal microbicide trial in this setting.

Trial registration

Current Controlled Trials ISRCTN64716212     

A Prospective Study of the Case-Notes of MRSA-Positive Patients: A Vehicle of MRSA Spread

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) has received much publicity and remains a major problem for the health service. The aim of this study was to determine whether case-notes of MRSA-positive patients can act as a vehicle for MRSA transmission.

PATIENTS AND METHODS

A prospective study was performed of patients with active MRSA infection identified from a microbiology department database. Two swabs were taken from the cover of the case-notes and the page with the most recent entry for identification of MRSA using MRSA ID (Chromogenic agar medium), Pastorex and DNase tests. Positive case-notes were re-swabbed 96 h later.

RESULTS

A total of 50 MRSA-positive patients were identified from medical, surgical, high dependency and intensive care Three sets of notes were MRSA positive (3/50; 6%). None of the positive case-notes was positive on re-swabbing at 96 h.

CONCLUSIONS

Case-notes of MRSA-positive patients can act as carriers of MRSA with the potential to spread MRSA to both healthcare and non-healthcare workers without direct contact with infected patients. We recommend extending the universal precautions to the handling of case-notes belonging to MRSA-infected patients.     

Apical hypertrophic cardiomyopathy might lead to misdiagnosis of ischaemic heart disease

Purpose In this study, demographic, clinic, electrocardiographic and angiographic properties of patients, on whom coronary angiography was performed with the pre-diagnosis of coronary artery disease (CAD) and whose ventriculography demonstrated typical apical hypertrophic cardiomyopathy (AHCM), were investigated. Methods Seventeen patients (mean age 58 +/- 10 years, 10 male) with CAD pre-diagnosis, on whom coronary angiography was performed and had typical spade-like appearance on left ventriculography, were included in the study between January 2000 and May 2005. Results As risk factor for CAD, 8 (47%) patients had hypertension, 8 (47%) patients had dyslipidaemia, 2 (11%) patients had type 2 diabetes mellitus, 13 (77%) patients had a history of smoking, and 2 (11%) patients had family history. Seven (42%) patients presented unstable angina pectoris, 8 (47%) patients presented stable angina pectoris and 2 (11%) patients were asymptomatic. On coronary angiography, it was determined that 10 (58%) patients had normal coronary arteries, 3 (17%) patients had non-significant stenosis and 4 (25%) patients had myocardial bridging. Five (30%) patients revealed mid-ventricular obstruction and intraventricular gradient was 25 +/- 5 mmHg by the catheterization. All patients showed 'giant' negative (>/= 10 mm) T waves in the precordial leads, whereas 2 patients had atrial fibrillation. Maximum wall thickness was measured as 18 +/- 4 mm in the apical region by transthoracic echocardiography. One patient (5%) who had mid-ventricular obstruction developed atrial fibrillation during 2 years follow-up, though any other events did not occur during hospitalization or follow-up period. Conclusions Physicians caring for patients with chest pain should consider AHCM in their differential diagnosis in case of a patient with chest pain and electrocardiographic changes suggestive of CAD.     

Prognostic value of plasma soluble CD40 ligand in patients with chronic non-valvular atrial fibrillation.

AIMS: We aimed to clarify whether determination of levels of soluble CD40 ligand (sCD40L) could predict subsequent thrombo-embolic events in patients with non-valvular atrial fibrillation (NVAF). METHODS AND RESULTS: Forty-four consecutive outpatients (mean age: 58 +/- 6 years, 20 male) with chronic NVAF who were not receiving aspirin and had no thrombus or spontaneous echo contrast (SEC) on left atrium (LA) or left atrial appendage (LAA) were included in the study. The patients had no history of an embolic event and were followed up 24 +/- 2 months for thrombo-embolic events. sCD40L was determined at the enrollment. All patients were evaluated by means of SEC and thrombus formation by transoesophageal echocardiography at the end of follow-up period. Twelve (27%) patients had SEC and 2 (5%) patients had thrombus on LAA. Ischaemic stroke occurred in 2 (4.5%) patients and transient ischaemic attack developed in 4 (9%) patients during follow-up. sCD40L was significantly higher in patients with LASEC (0.41 +/- 0.05 vs. 0.16 +/- 0.04 ng/mL, P = 0.02) and embolic events (0.74 +/- 0.05 vs. 0.19 +/- 0.03 ng/mL, P = 0.001) than in those without. sCD40L levels were significantly related to the LASEC grade (R = 0.377, P = 0.02). In multivariable analysis, while independent variables for SEC or thrombus formation were LA diameter, sCD40L levels, and the duration of AF, independent variables for cerebrovascular events were the existence of SEC or thrombus formation on LAA, and sCD40L level. CONCLUSION: Plasma sCD40L may prospectively predict stroke in AF. sCD40L may provide useful marker to identify patients at high thrombo-embolic risk with NVAF.